1. Field of the Invention
This invention relates to t-alkylperoxysorbates having both conjugated diene and peroxidic groups in their molecule and to their use as free radical initiators in the formation of polymers and as comonomers in the formation of copolymers containing pendant peroxyesters.
2. Description of the Prior Art
Heretofore, there have been known some peroxides having a copolymerizable double bond. For example British Pat. No. 1041 088 discloses that t-butylperoxy methacrylate and methyl methacrylate are copolymerized whereby a copolymer having a peroxyester group is obtained and that the said copolymer is subjected to a graft copolymerization.
U.S. Pat. No. 3536,676 discloses that di (t-butylperoxy) fumarate and styrene are copolymerised whereby there is obtained a copolymer having a peroxyester group and the said copolymer and methyl acrylate are subjected to graft copolymerization.
Japanese Patent Publication SHO 38-5972 discloses that t-butylperoxycrotonate and vinyl chloride are copolymerised to thereby obtain a copolymer having a peroxyester group and the thus obtained copolymer and natural rubber latex are mixed at high temperature whereby blended polymers are obtained.
U.S. Pat. No. 3408 423 discloses that unsaturated polyester resins are cured at high temperature by using a curing catalyst whereby resins which are splendid in color and hardness are obtained.
The before mentioned compounds locate the peroxyester group and the double bond thereof in the .alpha. -- and .beta. -- positions in their formula. However Japanese Patent Publication SHO 44-21721 discloses that t-butylperoxy vinyl acetate locates them in the .beta. -- and .gamma. -- positions in the formula and resins which possess good extrusion properties and transparency are obtained by polymerizing ethylene using the said peroxide.
As mentioned above, the peroxyesters having a polymerizable double bond are superior to the peroxyesters not containing a double bond many points but the former peroxyesters also have some defects in them.
For example such compounds which selfpolymerize easily such as t-butylperoxy methacrylate as well as the acid chloride thereof which is the starting material therefor, are not stable while being stored and are inconvenient for handling.
Further, a compound which possesses high copolymerization reactivity such as di(t-butylperoxy) fumarate can not distribute the peroxyester group in the polymer uniformly in a broad range of the concentration thereof. Especially, when the concentration of the peroxyester is small, the peroxyester do not give a good copolymer. T-butylperoxy crotonate is small in copolymerisation reactivity with a conjugated monomer having an Alfrey-Price value of more than 0.3, such as styrene, and as a result it is not suitable for copolymerisation pg,4 with the monomer. Further, t-butylperoxy vinyl acetate is bad in heat stability and is unsuitable as a copolymerizable monomer.
As mentioned above, there have been disclosed peroxyesters having polymerizable double bonds but peroxyesters having conjugated diene group have not been described heretofore.